Method of making combined sponge rubber-textile materials



Sept- 18, l951 E. B. LEWIS 2,567,953

METHOD .oF MAKING CMBINED sPoNGE RUBBER-.TEXTILE MATERIALS `originan Filed April 7, 1948 FIGZ IIL

ELISHA B. .LEWIS Patented Sept. 18, 1951 METHOD OIF-MAKING COMBINED SPONGE RUBBER-TEXTILE vMATERIALS Elisha B. Lewis, Dayton, ohio, assignor to 'rho Commonwealth Engineering Company of Ohio, Dayton, Ohio, a corporation` of Ohio original application April -7, 194s, serial No. 19,568. Divided and this application November 15, 1949, serial No. 127,560

This application deals with a combined sponge rubber-textile material and a method of making it and is a division of application Serial No. 19,-

568 filed April '7, 1948. The material of my invention has a great many uses as will be pointed' out later, however, it isespecially well suitable forV iioor coverings, such as rugs, carpeting and mats.

Floor covering material, especially when applied to hardwood oors, requires a paddingin order to increase 'the grip of the carpeting with the oor and avoid that the floor covering becomes displaced. Such paddings have `a number of disadvantages. During use, for instance when being walked on, the padding becomes displaced and after a while shows at the edges which gives a very unneat appearance. Moreover, dirt accumulated in the floor covering material falls through its porous base so that, for removing all of the dirt the. floor covering has to be removed in order to have access to the padding. This is rubber-textile material in which the rubber covers the back of the textilematerial and penetrates and ills the interstices thereof without appearing on the face of the textile material.

It is another object of this invention to provide` a rubber-textile material which has a good gripping action so' that it does not become dislocated duringf used.

It is another object, of this invention lto provide a rubber-textile material `which has great softness and a high cushioning eiect.

It is still another object of this invention to provide a rubber-textile material which is highly resilient so 'that impressions formed in the material disappear after the pressure causing such impressions has ceased; by this the material always resunlesits original appearance and looks like new even after being used for a long period of time'.

It is still another object of this invention-to provide a rubber-textile material which may hecut to size and does not fray at its edges so that the customary step of binding the edges 'with tape or the like may be dispensed with.

It is still another object ofthis invention rto 9 claims.' (01.154-139) provide a rubber-textile material which is highly exible so lthat it may be rolled up for the purpose of storage, shipping and the like.

' It is still another object of this invention to Aprovide a rubber-textile material which has sound-proong characteristics. K

It is still another object of this invention to provide a rubber-textile material which is ameresistant.'

It is still another object of this invention to provide a oor covering material having a nap the fibers of which are firmly anchored to the base which is responsible for a long service life. l It is still another object of this invention to provide floorcovering material having a nap which always reassumes its upright position whereby its new appearance is retained.

It is vstill another object of this invention to provide floor covering materials on which furniture, when moved, does not leave permanent marks.

It is still another object of this invention to provide oor covering materials in which, when combined of a plurality of strips, the seams are practically invisible on the face of the iioor covering. f

These and other objects, are accomplished by introducing nitrous oxide gas into a mixture of rubber latex and sodium silicate solution while subjecting said mixture to high-speed agitation whereby a rubber foam is produced, thereafter depositing said rubber foam still in fluid form on the back of the textile material to be treated and finally curing said foam on said textile material.

The process of my invention may be carried out in a continuous as well as a, discontinuous operation, An apparatus suitable for manufacturing the material o'f this invention is ydescribed in detail in my (zo-pending application Serial No. 13,605 led March 8, 1948, entitled Method of Making Sponge Rubber, now abandoned.

While the quantity of sodium silicate may vary within wide ranges, it has been found that particularly good results are obtained with a proportion of substantially 2.25 per cent by volume of sodium silicate solution with regard to the latex. It has also been found that while nitrous oxide gas may beintroduced underl pressure, the use of high speed stirring is superior thereto,

- well as of theapparatus for carryingl out the pl'OCeSS.

Y WhileV most kinds vof Synthetic and natural latices are satisfactorily operative for the process of my invention, it has been found that neoprene latex yields the very best results.

The addition of sodium silicate makes refrigeration of the latices unnecessary, since it pre vents coagulation and acts as a curing decelerator. A quantity of 20 per cent sodium silicate for example, was used in one instance in order to dispense with refrigeration; however,- 2.25 per cent by volume with regard to the latex yield the same favorable effect and in addition thereto have the advantage of producing a still higher volume increase than was obtained with 20 per cent of the agent. This nding was quite unexpected and contrary to logical reasoning.

The sodium silicate solution preferably used has a density of 41 B. and a ratio of alkali to silica of 1 to 3.22. The latices are advantageouslir employed in a concentration of or about 50 per cent.

High speed stirring may either be carried out by employing a simple stirrer and `moving it up and down during operation so as to cause agitation in all layers or levels of the liquid, or else a so-called compound stirrer, which is one having a plurality of blades or vanes at its axle shaft, may be used. A speed of up to 5,000 R, P. M. has proven suitable.

It will also be satisfactory to combine the high speed agitation with the application of pressure. By this a still 'greater volume increase is cbtained; however, since the application of pressure complicates the apparatus, it is a question of economy as to whether it is preferable to sacrice a certain degree of porosity for the advantage of lower cost or whether to produce with the highest efficiency disregarding the cost of production.

After the foam has been prepared it is deposited while still in fluid condition onto the back of the textile material. Thereafter the combination is cured; while curing may be carried out in an oven, the use of infra-red light has been found preferable. Exposure for a time of from 15 to 20 minutes gave satisfactory results. If a backing of considerable thickness, for instance of 1" or more, is to be applied, it was found advisable to prepare, deposit and cure the foam ininstallments. This is carried out by rst depositing a foam layer of, say, 1A" thickness, heating for l5 to 20 minutes, superposing another foam layer of about the same thickness and curing the added layer. These steps are repeated until a product of the desired thickness is obtained. The sponge product by this stepwise procedure does not show any lines of separation; it is an integral unit and has the same excellent qualities as sponge produced by the one-step process.

For the vulcanization with infra-red light, a voltage of 115 volts and 37 5-watt lamps were used. The distance of the lamps from the rubber surface was approximately 16".

tageous for the production of combined sponge rubber-textile material by the process of my invention. This example, it will be understood, is given merely for the purpose of illustration but not for that of limitation.

Example Neoprene latex cc- 400 Sodium silicate solution (41 B.) cc 9 Light viscosity vegetable oil of cottonseed oil base ce 8 25% dispersion of sodium silicofluo ride cc-- 9.2

The ingredients are added in the order given above under rapid agitation with a compound stirrer. After the plasticizer such as a llight viscosity vegetable oil is added, nitrous oxide is introduced; the mixture is foamed therebyand its volume increased by about 450%. Thereafter the sensitizer such as sodium Silico-fluoride dissolved in approximately 50 cc. water is added While still continuing the stirring operation. From the foam thus obtained, a 1/4 thick layer is poured It will be understood that the latex composie tions used for the process of my invention may contain other additional ingredients than those mentioned in the example given. For instance, latices containing accelerators, vulcanizin'g agents and other auxiliary materials customary and Well known to those skilled in the art are within the scope of my invention. Likewise, the compositions of the latex and the curing conditions may be chosen so as to obtain a final product of the desired degree of hardness.

It will also be understood that the term textile materials comprisesnot only woven fabrics,

Another very satisfactory modification of carsince the invention is equally well applicable to matted materials. If a completely non-inflammable material is desirable, glass fibers, either matted or Woven, are advantageous.' Such glass bers-sponge rubber com'bination is also satisfactory as heat insulating material` One of the prime advantages obtained with the rubber foam made according to the invention is that a non-inflammable product is obtained. The sponge rubber also makes the material soundproof which is especially valuable in the case of carpeting material and portieres. .Since the sponge rubber is integrally united with the textile material and, in the case of carpeting, the nap is securely anchored by the sponge rubber, an excellently durable floor covering is obtained.

The interstices of the textile material 'fbeing lled lwith rubber, the dust accumulated in the covering cannot fall through so that lifting of the carpeting is not necessary for cleaning purposes. The nap always retains its upright position due to the resiliency of the rubber material. Floors covered with the material of this invention are not as tiring as other floors having the conventional carpeting in View of the high cushioningL effect and resiliency of the sponge rubber. No dislocation of a separate pad occurs which is another advantage of the article of my invention.

. bers, including the Furniture, which usually makes deep and permanent impressions in carpeting material so that the marks remain and spoil the appearance of the carpet'when that furniture is moved, does not have any permanent effect on the carpeting of the invention, no matter how heavy the furniture is. The rubber provides for such a high degree of resiliency that the yoriginal appearancev is always resumed shortlyafter impressions have been made on the nap. Whereas carpeting when cut to size has to be bound at the edges by means of tape in order to avoid fraying, the material of my invention does not require such treatment ofthe edges since the nap, are firmly anchored by the rubber layer.

In the accompanying drawings. some embodiments of the products of the invention are diagrammatically illustrated.

Figure 1 is a. plan view of a fabric used for the process of my invention;

Figure 2 is a cross sectional view taken along ing 100 parts .by volume of a rubber latex having a concentration of approximately 50 per cent with 2.25 parts by volume of a. sodium silicate solution of 41 B..` and a proportion of alkali to silica of 1:32; (b) introducing nitrous line 2-2 of Figure 1 showing the structure of the nished product;

Figure 3 is a plan view cfa carpeting composed of three strips; and

Figure 4 is'across sectional view taken along line 4-4 of Figure 3.

vReferring to the drawings, in particular the' reference numeral I0 designates warp threads `of a fabric and II its iiller threads. In Figure 2,

nap fibers I2 which extend from said fabric are visible. A layer of sponge rubber I 3 is'applied to the back of said fabric and it may be readily seenv that the sponge rubber Ipenetrates the interstices of the fabric and thereby anchors the nap firmly to the fabric.` The sponge rubberhas a great number of uniformly distributed discrete cells I4.

Figure 3 illustrates a carpeting piece I5 composed of three strips -I 6, I1 and I8. The strips are sewn together at the'seams I9 andy 20. A

sponge rubber layer 2l has been applied to said combined carpeting material. It will be seen from Figure 4 that this sponge rubber no t only penetrates the interstices of the fabric but also the seams I9 and 20 and thereby anchors the strips and combines them into one integral unit. The nap layer 22 of the carpeting material I5 does not show any irregularity or spacing above the seams I9 and 20 so that the carpeting has the appearance of one single piece.

The material of the invention lends itself to a great many applications. It has been used with great satisfaction for rugs, carpeting, floor mats, draperies, portieres, chair cushions, and upholstering material. Other uses may be found once the excellent qualities and characteristics of the material of the invention have become known.

It will be understood that while there have I been disclosed hereincertain specific embodiments of my invention it is not intended thereby to have the invention limited to the details given in view of the fact that it is susceptible `to various modications and changes which come within the spirit of the disclosure and the scope of the appended claims.

I claim: i

1. In a process for making combined sponge l rubber-textile materials the steps of (a) mixing rubber latex with sodium silicate solution;

(b) introducing nitrous oxide gas while subjecting the mixture to agitation whereby arubber foam is produced; (c) depositing said rubber foam on the back of said textile material while oxide gas while subjecting the mixture to agitation whereby a rubber foam is produced; (c) depositing said rubber foam on the back of said textile-material while in a nuid form; and (d) curing said foam thereon.

4. In a process for making combined sponge rubber-textile materials the steps of (a) mixing rubber latex with sodium silicate solution and from 3 to 5 per cent of a high alpha-cellulose; (b) introducing nitrous oxide gas while sub-v jecting the mixture to agitation whereby a rubber foam is produced (c) depositing said rubber foam on the back of said textile material while in a fluid form; and (d) curing said foam there- 5. In a process for making combined sponge rubber-textile materials the steps of (a) mixing neoprene latex with sodium silicate solution; (b) introducing nitrous oxide gas while subjecting the mixture to agitation whereby a rubber foam is produced; (c) depositing said rubber foam on the back of said textile material while in a. uid form; and (d) curing said foam thereon.

6. In a process for making combined sponge rubber-textile materials the steps of (a) mixing rubber latex with sodium silicate solution; (b)

introducing nitrous oxide gas under pressure while subjecting the mixture toyagitation whereby a rubber foam is produced;` (c) depositing said rubber foam on the back of said textile material while in a uid form; and (d) curing said foam thereon.'

'1; In a process' for making combined sponge rubber-textile materials the steps of (a) mixing rubber latex with sodium silicate solution; (b) introducing nitrous oxide gas while subjecting the mixture to agitation whereby a rubber foam is produced; (c) depositing said rubber foam onV the back of said textile material while in a uid form; and (d) curing said foam thereon for 'aiigipioximately 15 to 20 minutes with infra-red '8. In a process for making combined sponge rubber-textile materials the steps of (a) mixing rubberlatex with sodium silicate solution; (b) introducing nitrous oxide gas while subjecting the mixture to agitation whereby a rubber foam is produced; (c) depositing a thin layer .of rubber foam while still iiuid on the back of said textile material; (d) curing said foam on said Y textile material; (e) superposing another thin layer of rubber foam onto said first layer; (f) curing said second layer; and (g) repeating said deposition of layers and curing until a sponge rubber back of the desired thickness has been obtained.

9. In a process for making carpets the steps ademas 7 o! uniting a. plurality of strips of textile material. said textile material having a napped surface; mixing rubber latex with sodium silicate solution; introducing nitrous oxide gas while subjecting the mixture to agitation whereby a rubber foam is produced; depositing said rubber foam on the back of said combined carpet; and curing said foam on said carpet whereby the strips are nrmly bonded to each other, the said rubber layer integrally united with said textile material, the lnterstices of said textile material lled with said rubber and the fibers of said nap iirmly anchored to said textile material. v

ELISHA B. LEWIS.

8 REFERENCES orrEn The following references are of record in the die of this patent:

UNITED STATES PATENTS i Number Name Date 1,030,446 Allen June 25, 1912 1,845,688 Untiedt Feb. 16, 1932 2,092,825 Behr Sept. 14, 1937 2,126,273 Ogilby Aug. 9, 1938 2,163,289 Pennel et ai. June 20, 1939 2,288,190 Harrison June 30, 1942 2,321,111 Stamberger June 8, 1943 

1. IN A PROCESS FOR MAKING COMBINED SPONGE RUBBER-TEXTILE MATERIALS THE STEPS OF (A) MIXING RUBBER LATEX WITH SODIUM SILICATE SOLUTION; (B) INTRODUCING NITROUS OXIDE GAS WHILE SUBJECTING THE MIXTURE TO AGITATION WHEREBY A RUBBER FOAM IS PRODUCED; (C) DEPOSITING SAID RUBBER FOAM ON THE BACK OF SAID TEXTILE MATERIAL WHILE IN A FLUID FORM; AND (D) CURING SAID FOAM THEREON. 